Hi, I just got my 2004 RX8, and need to replace the "Reverse Switch". I bought Y612-17-640B from Ebay, but Sake Bomb said it is wrong. I checked carefully in this thread. Some said 640B is Neutral, some said 640B is Reverse. Could any one help to clarify? I'm planning to order directly from JDM-Planet. Thanks a lot!

640B is neutral. Y611-17-640A is the reverse.

Thank you Killawatts!!

Finally got the correct part, PN is Y611-17-640A for Reverse Switch (Black connector with an o ring as shown on picture). The explodes 3D drawing in this thread shared by others has been misleading everyone for years. It shows the Y612-17-640B on the Reverse Switch side. Most of us were fooled by that drawing and picked the wrong PN. Hope these pictures will help other RX8 owners to pick the right switch they need when search in this Forum.

Also, just to share with those who don't know how to DIY, we were charged 0.7hour*$165+ 75W-90 Gear Oil $28 + Tax 2.59 + Fill Oil Labor 0.5*$165 = $228.09 Because they said when replacing the switch the gear oil will leak a bit. The cost of switch is $79.98. Just to keep your hands clean by getting someone to put the switch back, the total cost is $308.07 in Bay Area. Oh, I forgot to add on two trips of UBER, over $50.

After dealing with issue, I will need to fix my power steering light. Left the car at the garage for half a week, nothing found, even I provided the feedback from dealer. They said the issue was intermittent and charged me 0.5hour*$165 = $82.5 for "check and advice, and inspect harness for damage" (by the way, my RX8 was with a customized intake, no need to remove tons of parts from the original intake. Anyway...... I will check on other repair shop after this experience or start to learn how to take care my new baby from now on.

https://cimg3.ibsrv.net/gimg/www.rx8...9987ce04d9.jpg


https://cimg3.ibsrv.net/gimg/www.rx8...ea9e48a35c.png
This is indeed Y611-17-640A, not 640B as sown on the exploded drawing.
https://cimg2.ibsrv.net/gimg/www.rx8...d994b17bb4.png

https://cimg5.ibsrv.net/gimg/www.rx8...3edb383916.png

no, different transmission manufacturers, different sensors, different electrical connectors between the two.
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This was all the help I came for.... but a question arises. It's discussed in this thread that if neutral switch is disconnected idle is going to be crap. What happens if the reverse switch is not connected? Looking under my car one of the black connectors looks like it was not plugged in but I've had no issues with getting into reverse and my reverse lights operate just fine. I'm trying to determine if I unplugged it and forgot I did before I snapped a photo (I'm removing my engine harness), or if it has been disconnected this entire time.

I think its the clutch switch that screws up the idle......

no, the rpms will surge up and down ~1000 rpm in neutral if the neutral switch is not detected or bad/defective.

I had a trans rebuilt and the shop put a sealing washer on the neutral switch, but it doesn’t have one from Mazda. So the thickness of the washer wasn’t letting pcm receive the switch signal and it had that problem. I’m not even sure how we figured it out, maybe on a code reader. It was a ling time ago, but the same thing happens if the switch is bad or one or both connectors are unplugged.

It may not need the switch or not cause the same issue with the Adaptronic pcm is another thing to consider.
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So if one of the reverse connectors (black) wasn't connected what would happen? Would you even notice while driving the car? Would it prevent the trans from engaging reverse?

no, it’s just a switch that turns on the reverse lights when engaged; there’s a notch in the gear selector shaft that determines this, same for the neutral switch, that’s all they do/are

if you look at the switch photo in the previous posts above; the ball-shaped piece on the end of it is internally spring-loaded to extend outward as in the photo. So when it’s in the notch on the shaft it can extend fully, otherwise the unnotched section of the selector shaft keeps it pressed inward and not engaged.
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Beauty thanks, I must have unplugged the first connector before my brain caught up with me since my reverse lights were working haha

the plugs look the same for both switches, so possibly it was for the other, not really sure how to explain it because obviously as a simple on/off continuity switch it can’t ever make continuity if one on the two wires is disconnected :dunno: so logically the simple conclusion is ….


https://cimg4.ibsrv.net/gimg/www.rx8...376c89134a.gif
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Yes we are saying the same thing, it had to have been connected for reverse lights to work. While prepping my engine for removal I've been labelling everything and taking photos before I start disconnecting things. After I removed the harness I noticed the photo I took while under the car showed one of the black plugs disconnected. I likely, not thinking, disconnected it prior to taking the photo but I couldn't actually remember, so I was just double checking what would happen if it was disconnected the whole time, which I now know wasn't the case based on the above info. Thanks again for your input on the matter!